Recent progress in power rectifiers and their applications

The paper gives a general survey of the present stage of development of power rectifiers. Recent innovations in the design of rectifier types are described, and some of the limitations arediscussed. The subject matter mainly concerns rectifiers of the mercury-arc type, including water-cooled rectifiers, glass-bulb rectifiers, pumpless air-cooled steel-tank rectifiers, and igniter types. Thesevarious rectifiers represent a voltage range from 200 volts to 50 kV (d. c), and currents up to about 10 000 amperes. Reference is also made to some of the leading non-vacuum rectifiers, such as jet-wave rectifiers, gas-cooled arc types, and electrolytic and mechanical types. Most of these are still in course of development, and an indication of the progress achieved is given. The more direct methods of controlling the output of the mercury-arc rectifiers by means of control grids are mentioned, and in this connection voltage regulation, inversion, and arc suppression, are discussed. General features of rectifier equipment are considered, together with some aspects of rectifier auxiliaries. The scope and performance of rectifier installations are also indicated, special reference being made to railway electrification, highvoltage working, and the applications of grid control. Finally, some suggestion of the possible trend of future developments is given.